Steam-engine indicator.



UNITED STATES THEODORE DAVIDSON, OF SALEM, MASSACHUSETTS, ASSIGNOR TOCROSBY STEAM GAGE & VALVE COMPANY,

PORATION OF MASSACHUSETTS.

OF BOSTON, MASSACHUSETTS, A COR- STEAM-ENGINE INDICATOR.

SPECIFICATION forming part of Letters Patent No. 713,611, dated November18, 1902.

Application filed May 10,1901.

To @ZZ whom, it may concern;

Be it known that I, THEoDoRE DAVIDSON, a citizen of the United States,and a resident of Salem, in the county of Essex and State ofMassachusetts, have invented certain new and useful Improvements inSteam-Engine Indicators,of which the following is a specification.

My invention relates to steam-engine indicators in which a sphericalpiston, in conjuncra tion with a steam-cylinder and a spring-operatedpiston-rod, is employed to operate a peucil mechanism; and its objectsare, first, to provide a piston which shall operate with the leastpossible friction and adapt itself readily to any inequalities in thepressure or to other disturbing features; second, to provide anindependent rod for actuating the pencil mechanism and means forsecuring its vertical movement; third, to provide means for adzo justingthe height of the pencil on the drum, and thus enable one to fixconveniently the atmospheric line on the diagram carried by the drum asdesired.

My invention is illustrated by the accompanying drawings, in which-Figure 1 is an elevation, partly in section, of the entire mechanism.Fig. 2 is an elevation, partly in section, of the pencil mechanism,piston, piston-rod, and lower portion of 3o the spring. Fig. 3 is anelevation, partly in section, of the upper end of the piston-rod andswivel attachment. v

Similar letters refer to similar parts throughout.

A is a steam-cylinder furnished with the bushing a, to which is attachedthe coupling a', furnished also with the removable cap ce2, the arm 0.3for supporting the paper drum M, the exhaust-ports a4, and the pin a5for hold- 4o ing the annular base b in place.

B is a frame consisting of the annular base b, adapted to encircle thecylinder A, the posts b', fixed to said base, and the yoke h2, attachedto said posts and held in position by the nuts h3 and furnished with thethreaded projection b4.

C is the piston, threaded for engagement with the piston-rod D, which Iprefer to call the spring-operated rod, and with the cap- Serial No.59,668. (No model.)

screw G, which is hollowed out to receive the 5o ball g, formingtherewith a universal joint.

The piston-rod or spring-operated rod D is slotted and bored to receivethe pencil mechanism, threaded at its upper end for engagement with theswivel-pin d, Fig. 3, threaded 55 at its lower end for engagement withthe pistou, and hollowed out to receive the ball g.

E is the spring, made of a single piece of wire wound from its middlepoint e into a double coil, the spiral ends of which are 6o screwed intoa brass head c', having four radial wings, with spirally-drilled holesto receive and hold them securely in place. This brass head c' isthreaded for longitudinal adjustment on and engagement with theprojection l and is held in adjustment thereon by the check-nut e2.

The pencil mechanism F consists of the rod f, attached at its lower endto the ball g, the link f, the link f2, attached to the post h, the 7opencil-leverfS, and the link f4, attached to the posts 71,'. These postsh 7i' are supported by the sleeve H, which has a rotary motion, limitedby the posts b', but whose vertical motion is prevented by the nut h2.this sleeve H is the bracket h3, adapted to guide the rodf and limit itsmotion to a vertical.

I is a swivel having a slot t' for receiving the spring E and threadedto receive the cap- 8o screw J.

K is a handle with a threaded shank which engages the threaded arm 7c ofthe sleeve H and by contact with the post b adjusts the contact of thepencil]c5 with the paper drum M.

The annular base b is rotatable about the cylinder A and is locked inplace bythe peg a5.

The principal feature of my invention is the piston C, which is thecentral zone of a sphere, whose diameter is just enough less 9o than thediameter of the steam-cylinder to permit its use as a piston. The Zonemay be of any width desired, or the piston may be a sphere. The contactbetween the cylinder and piston will be approximately a line, and it isObvious that the pistonmay deviate from its horizontal position in thecylinder without increasing the area of Contact and that this Fixed to75v i tion with a steam-cylinder and a piston conarea of contact willalways be approximately a line constituting a circumference of thesphere, of which the piston constitutes a zone. The object of thisspherical piston is to reduce the friction to a minimum and to avoid theinjurious eects of friction arising from any cause.

Another feature of my invention is the rod f, adapted to actuate thepencil mechanism. This rodf is limited to a Vertical movement by thebracket-guide h3 and the ball g and is undisturbed by any deviation ofthe pistonrod or spring-operated rod D from its Vertical.

`That the piston,"pistonrod, and rod or spring-operated rodf maynormally have the same Vertical axis I have bored and slotted thepiston-rod or spring-operated rod for the reception of rodf and thepencil mechanism.

The swivel I enables one to screw the springhead e' upon the frame B toany desired extent,thus providing for the adjustment to any heightdesired of the pencil on the paper drum. The check-nut e2 provides formaintaining this adjustment. The cap-screw J holds the spring in theslotted swivel I. To explain more fully this function of the spring, Iwill say that the spring E (being thus longitudinally bodily adjustableupon the frame B by means of the threaded engagement of the head e withthe projection b4 and operating the pencil-mechanism rod f by means ofthe spring-operated rod D and piston C) enables the operator by raisingor lowering the spring to raise or lower the pencil f5 on the drum M,and thus to tix conveniently the atmospheric line on the diagram carriedby the drum M as he may desire. The spring being thus fixed to the frameB and to the swivel-head of the piston-rod acts in extension and not bycompression.

Having described my invention, what I claim, and desire to secure byLetters Patent, 1s-

l. Inasteam-engine indicator the combination, with a steam-cylinder anda spherical piston, ofa spring-operated rod in engagement with saidpiston, a spring adapted to operate said rod, and a pencil mechanismoperated by said rod; substantially asdescribed.

2. In a steam-engine indicator the combinasisting of a central zone of asphere, of a spring-operated rod in engagement with said piston, aspring adapted to operate said rod, and a pencil mechanism operated bysaid rod; substantially as described.

3. In asteam-engine indicator the combination, with a steam-cylinder andaspherical piston, of a spring-operated rod in engagement with saidpiston, a spring adapted to operate said rod, a pencil mechanismoperated by said rod, and a paper drum whereon the pencil records itsmovements; substantially as described.

4. In a steam-engine indicator the combination, with a steam-cylinderand a piston consisting of a central zone of a sphere, of aspring-operated r'od in engagement with said piston, a spring adapted tooperate said rod, a pencil mechanism operated by said rod, and a paperdrum whereon the pencil records its movements; substantially asdescribed.

5. In a steam-engine indicator the combination, with a steam-cylinderand a spherical piston, of a spring-operated rod in engagement with saidpiston, a spring adapted to operate said rod, a pencil mechanism and inengagement therewith an independent pencil-mechanism rod joined at itslower end to the piston by a ball-and-socket joint, together with meansfor limiting the motion of said independent rod to a vertical;substantially as described.

6. In asteam-engineindicator the combination, with a steam-cylinder anda piston consist/ing of a central zone of a sphere, of a spring-operatedrod in engagement with said piston, a spring adapted to operate saidrod, a pencil mechanism and in engagement therewith an independentpencil-mechanism rod joined at its lower end to the piston by aballand-socket joint, together with means for limiting the motion ofsaid independent rod to a Vertical substantially as described.

7. In a steam-engine indicator the'combination, with a steam-cylinderand a spherical piston, of a spring-operated rod in engagement with saidpiston, a spring adapted to operate said rod, a pencil mechanism and inengagement therewith an independent pencil-mechanism rod joined at itslower end' to the piston bya ball-and-socket joint, together lOO withmeans for limiting the motion of said independent rod to a vertical, anda paper drum whereon the pencil records its movements; substantially asdescribed.

8. In a steam-engineindicator the combination, with a steam-cylinder anda piston consisting of a central zone of a sphere, of a spring-operatedrod in engagement with said piston, a spring adapted to operate saidrod, a pencil mechanism and in engagement therewith an independentpencil-mechanism rod joined at its lower end to the piston by aballand-socket joint, together with means for limiting the motion ofsaid independent rod to a vertical, and a paper drum whereon the pencilrecords its movements; substantially as described.

9. In a steam-engine indicator the combination, with a steam-cylinderand a spherical piston, of a spring-operated rod in engagement with saidpiston, a longitudinally-adj ustable spring adapted to operate said rod,and a pencil mechanism operated by said rod; substantially as described.

10. In a steam-engine indicator the combination, with a steam-cylinderand a piston consisting of a central zone of a sphere, of akspring-operated rod in engagement with said piston, alongitudinally-adjustable spring adapted to operate said rod, and apencil IIO mechanism operated by said rod; substantially as described.

11. In a steam-engine indicator the combination, with a steam-cylinderand a spherical piston, of a spring-operated rod in engagement with saidpiston, a longitudinally-adjustable spring adapted to operate said rod,a pencil mechanism operated by said rod, and a paper drum whereon thepencil records its movements; substantially as described.

12. In a steam-engine indicator the combination,with a steam-cylinderand a piston conl sisting of a central zone ot' a sphere, of aspring-operated rod in engagement with said piston, a longitudinallyadjustable spring adapted to operate said rod, a pencil mechanismoperated by said rod, and a paper drum whereon the pencil records itsmovements; substantially as described.

13. In a steam-engine indicator the combination, with a steam-cylinderand a spherical piston, of a spring-operated rod in engagement with saidpiston, a longitudinally-adjustable spring adapted to operate said rod,a pencil mechanism and in engagement therewith an independentpencil-mechanism rod joined at its lower end to the piston by aballand-socket joint, together with means for limiting the motion ofsaid independent rod to a vertical; substantially as described.

14. In a steam-engine indicator the combination,withasteam-eylinderandapiston consisting of a central zone of a sphere, of a spring-operatedrod in engagement with said piston, a longitudinally adjustable springadapted to operate said rod, a pencil mechanism and in engagementtherewith an independent pencil-mechanism rod joined at its lower end tothe piston by a hall-and-socket joint, together with means for limitingthe motion of said independent rod to a vertical; substantially asdescribed.

15. In a steam-engine indicator the combination, with a steam-cylinderand a spherical piston, of a spring-operated rod in engagement with saidpiston, a longitudinally-adjustable spring adapted to operate said rod,a pencil mechanism and in engagement therewith an independentpencil-mechanism rod joined at its lower end tothe piston by aballand-socket joint, together with means for limiting the motion ofsaid independent rod to a vertical, and a paper drum whereon the pencilrecords its movements; substantially as described.

16. In a steam-engine indicator the combination,with a steam-cylinderanda piston consisting of a central zone of a sphere, 0f a spring-operatedrod in engagement with said piston, a longitudinallyadjustable springadapted to operate said rod, a pencil mechanism and in engagementtherewith an independent pencil-mechanism rod joined at its lower end tothe piston by a ball-and-socket joint, together with means for limitingthe motion of said independent rod to a vertical, and a paper drumwhereon the pencil records its movements; substantially as described.

17. In a steam-engine indicator the combination, with a steam-cylinder,a spherical piston, and a spring-operated rod in engagement with saidpiston, of a longitudinally bodily adjustable spring adapted t0 operatesaid rod, with means for making the adjustment; substantially asdescribed.

1S. In a steam-engine indicator the combination, with a steam-cylinder,a piston consisting of a central zone of a sphere, and a spring-operatedrod in engagement with said piston, of a longitudinally bodilyadjustable spring adapted to operate said rod,with means for making theadjustment; substantially as described.

19. In a steam-engine indicator the combination, with a steam-cylinder`a spherical piston, and a spring-operated rod in engagement with saidpiston, of a longitudinally bodily adjustable spring adapted to operatesaid rod, means for making the adjustment, and means for maintaining theadjustment; substantially as described.

20. In a steam-engine indicator the combination, with a steam-cylinder,a piston consisting of a central zone of a sphere, and a spring-operatedrod in engagement with said piston, of a longitudinally bodilyadjustable spring adapted to operate said rod, means for making theadjustment, and means for maintaining the adjustment; substantially asdescribed.

In testimony whereof I have aftixed my signature in presence of twowitnesses.

THEODORE DAVIDSON.

Witnesses:

WATERMAN L. WILLIAMs, RALPH W'. FOSTER.

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